[clang-tools-extra] [clang-tidy] bugprone-assert-side-effect can detect side effect from non-const reference parameters (PR #84095)

[Congcong Cai via cfe-commits]

https://github.com/HerrCai0907 created https://github.com/llvm/llvm-project/pull/84095

Fixes: #84092

>From 160add4d95f34608a3d423482ad50fb45f6db522 Mon Sep 17 00:00:00 2001
From: Congcong Cai <congcongcai0907 at 163.com>
Date: Wed, 6 Mar 2024 06:55:30 +0800
Subject: [PATCH 1/2] [clang-tidy][NFC]refactor AssertSideEffectCheck logic

---
 .../clang-tidy/bugprone/AssertSideEffectCheck.cpp     | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/clang-tools-extra/clang-tidy/bugprone/AssertSideEffectCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/AssertSideEffectCheck.cpp
index 43bedd4f73ef44..25ca42bfd1bede 100644
--- a/clang-tools-extra/clang-tidy/bugprone/AssertSideEffectCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/AssertSideEffectCheck.cpp
@@ -60,16 +60,17 @@ AST_MATCHER_P2(Expr, hasSideEffect, bool, CheckFunctionCalls,
   }
 
   if (const auto *CExpr = dyn_cast<CallExpr>(E)) {
-    bool Result = CheckFunctionCalls;
+    if (!CheckFunctionCalls)
+      return false;
     if (const auto *FuncDecl = CExpr->getDirectCallee()) {
       if (FuncDecl->getDeclName().isIdentifier() &&
           IgnoredFunctionsMatcher.matches(*FuncDecl, Finder,
                                           Builder)) // exceptions come here
-        Result = false;
-      else if (const auto *MethodDecl = dyn_cast<CXXMethodDecl>(FuncDecl))
-        Result &= !MethodDecl->isConst();
+        return false;
+      if (const auto *MethodDecl = dyn_cast<CXXMethodDecl>(FuncDecl))
+        return !MethodDecl->isConst();
     }
-    return Result;
+    return true;
   }
 
   return isa<CXXNewExpr>(E) || isa<CXXDeleteExpr>(E) || isa<CXXThrowExpr>(E);

>From ce40ee88c708c8dcce8e5b2b9a1d000465e80c24 Mon Sep 17 00:00:00 2001
From: Congcong Cai <congcongcai0907 at 163.com>
Date: Wed, 6 Mar 2024 07:44:15 +0800
Subject: [PATCH 2/2] [clang-tidy] bugprone-assert-side-effect can detect side
 effect from non-const reference parameters

Fixes: #84092
---
 .../bugprone/AssertSideEffectCheck.cpp        | 11 +++++++++
 clang-tools-extra/docs/ReleaseNotes.rst       |  4 ++++
 .../checkers/bugprone/assert-side-effect.cpp  | 24 +++++++++++++++++++
 3 files changed, 39 insertions(+)

diff --git a/clang-tools-extra/clang-tidy/bugprone/AssertSideEffectCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/AssertSideEffectCheck.cpp
index 25ca42bfd1bede..2111047b9dff7a 100644
--- a/clang-tools-extra/clang-tidy/bugprone/AssertSideEffectCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/AssertSideEffectCheck.cpp
@@ -13,6 +13,7 @@
 #include "clang/ASTMatchers/ASTMatchFinder.h"
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/Lex/Lexer.h"
+#include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Casting.h"
@@ -67,6 +68,16 @@ AST_MATCHER_P2(Expr, hasSideEffect, bool, CheckFunctionCalls,
           IgnoredFunctionsMatcher.matches(*FuncDecl, Finder,
                                           Builder)) // exceptions come here
         return false;
+      for (size_t I = 0; I < FuncDecl->getNumParams(); I++) {
+        const ParmVarDecl *P = FuncDecl->getParamDecl(I);
+        const Expr *ArgExpr =
+            I < CExpr->getNumArgs() ? CExpr->getArg(I) : nullptr;
+        QualType PT = P->getType().getCanonicalType();
+        if (PT->isReferenceType() &&
+            !PT.getNonReferenceType().isConstQualified() && ArgExpr &&
+            !ArgExpr->isXValue())
+          return true;
+      }
       if (const auto *MethodDecl = dyn_cast<CXXMethodDecl>(FuncDecl))
         return !MethodDecl->isConst();
     }
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 0d2467210fc664..0d4d5ddb5c8763 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -122,6 +122,10 @@ New check aliases
 Changes in existing checks
 ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
+- Improved :doc:`bugprone-assert-side-effect
+  <clang-tidy/checks/bugprone/assert-side-effect>` check by detection side
+  effect from method call with non-const reference parameters.
+
 - Improved :doc:`bugprone-non-zero-enum-to-bool-conversion
   <clang-tidy/checks/bugprone/non-zero-enum-to-bool-conversion>` check by
   eliminating false positives resulting from direct usage of bitwise operators
diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone/assert-side-effect.cpp b/clang-tools-extra/test/clang-tidy/checkers/bugprone/assert-side-effect.cpp
index c11638aa823aae..5cdc1afb3d9099 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/bugprone/assert-side-effect.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone/assert-side-effect.cpp
@@ -108,3 +108,27 @@ int main() {
 
   return 0;
 }
+
+namespace parameter_anaylysis {
+
+struct S {
+  bool value(int) const;
+  bool leftValueRef(int &) const;
+  bool constRef(int const &) const;
+  bool rightValueRef(int &&) const;
+};
+
+void foo() {
+  S s{};
+  int i = 0;
+  assert(s.value(0));
+  assert(s.value(i));
+  assert(s.leftValueRef(i));
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: side effect in assert() condition discarded in release builds
+  assert(s.constRef(0));
+  assert(s.constRef(i));
+  assert(s.rightValueRef(0));
+  assert(s.rightValueRef(static_cast<int &&>(i)));
+}
+
+} // namespace parameter_anaylysis